[i-g-t,6/9] i915: Exercise preemption timeout controls in sysfs
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Message ID 20191113125240.3781-6-chris@chris-wilson.co.uk
State New
Headers show
Series
  • [i-g-t,1/9] i915/gem_exec_schedule: Split pi-ringfull into two tests
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Commit Message

Chris Wilson Nov. 13, 2019, 12:52 p.m. UTC
We [will] expose various per-engine scheduling controls. One of which,
'preempt_timeout_ms', defines how we wait for a preemption request to be
honoured by the currently executing context. If it fails to relieve the
GPU within the required timeout, the engine is reset and the miscreant
forcibly evicted.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 lib/i915/gem_context.c             |  41 ++++
 lib/i915/gem_context.h             |   2 +
 tests/Makefile.sources             |   1 +
 tests/i915/sysfs_preempt_timeout.c | 355 +++++++++++++++++++++++++++++
 tests/meson.build                  |   1 +
 5 files changed, 400 insertions(+)
 create mode 100644 tests/i915/sysfs_preempt_timeout.c

Patch
diff mbox series

diff --git a/lib/i915/gem_context.c b/lib/i915/gem_context.c
index 1fae5191f..aa083c2f0 100644
--- a/lib/i915/gem_context.c
+++ b/lib/i915/gem_context.c
@@ -403,3 +403,44 @@  bool gem_context_has_engine(int fd, uint32_t ctx, uint64_t engine)
 
 	return __gem_execbuf(fd, &execbuf) == -ENOENT;
 }
+
+static int create_ext_ioctl(int i915,
+			    struct drm_i915_gem_context_create_ext *arg)
+{
+	int err;
+
+	err = 0;
+	if (igt_ioctl(i915, DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT, arg)) {
+		err = -errno;
+		igt_assume(err);
+	}
+
+	errno = 0;
+	return err;
+}
+
+uint32_t gem_context_create_for_engine(int i915, unsigned int class, unsigned int inst)
+{
+	I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, 1) = {
+		.engines = { { .engine_class = class, .engine_instance = inst } }
+	};
+	struct drm_i915_gem_context_create_ext_setparam p_engines = {
+		.base = {
+			.name = I915_CONTEXT_CREATE_EXT_SETPARAM,
+			.next_extension = 0, /* end of chain */
+		},
+		.param = {
+			.param = I915_CONTEXT_PARAM_ENGINES,
+			.value = to_user_pointer(&engines),
+			.size = sizeof(engines),
+		},
+	};
+	struct drm_i915_gem_context_create_ext create = {
+		.flags = I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS,
+		.extensions = to_user_pointer(&p_engines),
+	};
+
+	igt_assert_eq(create_ext_ioctl(i915, &create), 0);
+	igt_assert_neq(create.ctx_id, 0);
+	return create.ctx_id;
+}
diff --git a/lib/i915/gem_context.h b/lib/i915/gem_context.h
index c0d4c9615..9e0a083f0 100644
--- a/lib/i915/gem_context.h
+++ b/lib/i915/gem_context.h
@@ -34,6 +34,8 @@  int __gem_context_create(int fd, uint32_t *ctx_id);
 void gem_context_destroy(int fd, uint32_t ctx_id);
 int __gem_context_destroy(int fd, uint32_t ctx_id);
 
+uint32_t gem_context_create_for_engine(int fd, unsigned int class, unsigned int inst);
+
 int __gem_context_clone(int i915,
 			uint32_t src, unsigned int share,
 			unsigned int flags,
diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index abf1e2fc1..413952c7c 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -98,6 +98,7 @@  TESTS_progs = \
 	tools_test \
 	vgem_basic \
 	vgem_slow \
+	i915/sysfs_preempt_timeout \
 	$(NULL)
 
 TESTS_progs += gem_bad_reloc
diff --git a/tests/i915/sysfs_preempt_timeout.c b/tests/i915/sysfs_preempt_timeout.c
new file mode 100644
index 000000000..4edc69c51
--- /dev/null
+++ b/tests/i915/sysfs_preempt_timeout.c
@@ -0,0 +1,355 @@ 
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "drmtest.h" /* gem_quiescent_gpu()! */
+#include "i915/gem_engine_topology.h"
+#include "igt_dummyload.h"
+#include "igt_sysfs.h"
+#include "ioctl_wrappers.h" /* igt_require_gem()! */
+#include "sw_sync.h"
+
+#include "igt_debugfs.h"
+
+static bool __enable_hangcheck(int dir, bool state)
+{
+	return igt_sysfs_set(dir, "enable_hangcheck", state ? "1" : "0");
+}
+
+static bool enable_hangcheck(int i915, bool state)
+{
+	bool success;
+	int dir;
+
+	dir = igt_sysfs_open_parameters(i915);
+	if (dir < 0) /* no parameters, must be default! */
+		return false;
+
+	success = __enable_hangcheck(dir, state);
+	close(dir);
+
+	return success;
+}
+
+static void set_preempt_timeout(int engine, unsigned int value)
+{
+	unsigned int delay;
+
+	igt_sysfs_printf(engine, "preempt_timeout_ms", "%u", value);
+	igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &delay);
+	igt_assert_eq(delay, value);
+}
+
+static void test_idempotent(int i915, int engine)
+{
+	unsigned int delays[] = { 0, 1, 1000, 1234, 654321 };
+	unsigned int saved;
+
+	/* Quick test that store/show reports the same values */
+
+	igt_assert(igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &saved) == 1);
+	igt_debug("Initial preempt_timeout_ms:%u\n", saved);
+
+	for (int i = 0; i < ARRAY_SIZE(delays); i++)
+		set_preempt_timeout(engine, delays[i]);
+
+	set_preempt_timeout(engine, saved);
+}
+
+static void test_invalid(int i915, int engine)
+{
+	unsigned int saved, delay;
+
+	/* Quick test that values that are not representable are rejected */
+
+	igt_assert(igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &saved) == 1);
+	igt_debug("Initial preempt_timeout_ms:%u\n", saved);
+
+	igt_sysfs_printf(engine, "preempt_timeout_ms", PRIu64, -1);
+	igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &delay);
+	igt_assert_eq(delay, saved);
+
+	igt_sysfs_printf(engine, "preempt_timeout_ms", "%d", -1);
+	igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &delay);
+	igt_assert_eq(delay, saved);
+
+	igt_sysfs_printf(engine, "preempt_timeout_ms", PRIu64, 40ull << 32);
+	igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &delay);
+	igt_assert_eq(delay, saved);
+}
+
+static void set_unbannable(int i915, uint32_t ctx)
+{
+	struct drm_i915_gem_context_param p = {
+		.ctx_id = ctx,
+		.param = I915_CONTEXT_PARAM_BANNABLE,
+	};
+
+	igt_assert_eq(__gem_context_set_param(i915, &p), 0);
+}
+
+static uint32_t create_context(int i915, unsigned int class, unsigned int inst, int prio)
+{
+	uint32_t ctx;
+
+	ctx = gem_context_create_for_engine(i915, class, inst);
+	set_unbannable(i915, ctx);
+	gem_context_set_priority(i915, ctx, prio);
+
+	return ctx;
+}
+
+static uint64_t __test_timeout(int i915, int engine, unsigned int timeout)
+{
+	unsigned int class, inst;
+	struct timespec ts = {};
+	igt_spin_t *spin[2];
+	uint64_t elapsed;
+	uint32_t ctx[2];
+
+	igt_assert(igt_sysfs_scanf(engine, "class", "%u", &class) == 1);
+	igt_assert(igt_sysfs_scanf(engine, "instance", "%u", &inst) == 1);
+
+	set_preempt_timeout(engine, timeout);
+
+	ctx[0] = create_context(i915, class, inst, -1023);
+	spin[0] = igt_spin_new(i915, ctx[0],
+			       .flags = (IGT_SPIN_NO_PREEMPTION |
+					 IGT_SPIN_POLL_RUN |
+					 IGT_SPIN_FENCE_OUT));
+	igt_spin_busywait_until_started(spin[0]);
+
+	ctx[1] = create_context(i915, class, inst, 1023);
+	igt_nsec_elapsed(&ts);
+	spin[1] = igt_spin_new(i915, ctx[1], .flags = IGT_SPIN_POLL_RUN);
+	igt_spin_busywait_until_started(spin[1]);
+	elapsed = igt_nsec_elapsed(&ts);
+
+	igt_spin_free(i915, spin[1]);
+
+	igt_assert_eq(sync_fence_wait(spin[0]->out_fence, 1), 0);
+	igt_assert_eq(sync_fence_status(spin[0]->out_fence), -EIO);
+
+	igt_spin_free(i915, spin[0]);
+
+	gem_context_destroy(i915, ctx[1]);
+	gem_context_destroy(i915, ctx[0]);
+	gem_quiescent_gpu(i915);
+
+	return elapsed;
+}
+
+static void test_timeout(int i915, int engine)
+{
+	int delays[] = { 1, 50, 100, 500 };
+	unsigned int saved;
+
+	/*
+	 * Send down some non-preemptable workloads and then request a
+	 * switch to a higher priority context. The HW will not be able to
+	 * respond, so the kernel will be forced to reset the hog. This
+	 * timeout should match our specification, and so we can measure
+	 * the delay from requesting the preemption to its completion.
+	 */
+
+	igt_assert(igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &saved) == 1);
+	igt_debug("Initial preempt_timeout_ms:%u\n", saved);
+
+	gem_quiescent_gpu(i915);
+	igt_require(enable_hangcheck(i915, false));
+
+	for (int i = 0; i < ARRAY_SIZE(delays); i++) {
+		uint64_t elapsed;
+
+		elapsed = __test_timeout(i915, engine, delays[i]);
+		igt_info("preempt_timeout_ms:%d, elapsed=%.3fms\n",
+			 delays[i], elapsed * 1e-6);
+
+		/*
+		 * We need to give a couple of jiffies slack for the scheduler timeouts
+		 * and then a little more slack fr the overhead in submitting and
+		 * measuring. 50ms should cover all of our sins and be useful
+		 * tolerance.
+		 */
+		igt_assert_f(elapsed / 1000 / 1000 < delays[i] + 50,
+			     "Forced preemption timeout exceeded request!\n");
+	}
+
+	igt_assert(enable_hangcheck(i915, true));
+	gem_quiescent_gpu(i915);
+	set_preempt_timeout(engine, saved);
+}
+
+static void test_off(int i915, int engine)
+{
+	unsigned int class, inst;
+	igt_spin_t *spin[2];
+	unsigned int saved;
+	uint32_t ctx[2];
+
+	/*
+	 * We support setting the timeout to 0 to disable the reset on
+	 * preemption failure. Having established that we can do forced
+	 * preemption on demand, we use the same setup (non-preeemptable hog
+	 * followed by a high priority context) and verify that the hog is
+	 * never reset. Never is a long time, so we settle for 150s.
+	 */
+
+	igt_assert(igt_sysfs_scanf(engine, "preempt_timeout_ms", "%u", &saved) == 1);
+	igt_debug("Initial preempt_timeout_ms:%u\n", saved);
+
+	gem_quiescent_gpu(i915);
+	igt_require(enable_hangcheck(i915, false));
+
+	igt_assert(igt_sysfs_scanf(engine, "class", "%u", &class) == 1);
+	igt_assert(igt_sysfs_scanf(engine, "instance", "%u", &inst) == 1);
+
+	set_preempt_timeout(engine, 0);
+
+	ctx[0] = create_context(i915, class, inst, -1023);
+	spin[0] = igt_spin_new(i915, ctx[0],
+			       .flags = (IGT_SPIN_NO_PREEMPTION |
+					 IGT_SPIN_POLL_RUN |
+					 IGT_SPIN_FENCE_OUT));
+	igt_spin_busywait_until_started(spin[0]);
+
+	ctx[1] = create_context(i915, class, inst, 1023);
+	spin[1] = igt_spin_new(i915, ctx[1], .flags = IGT_SPIN_POLL_RUN);
+
+	for (int i = 0; i < 150; i++) {
+		igt_assert_eq(sync_fence_status(spin[0]->out_fence), 0);
+		sleep(1);
+	}
+
+	set_preempt_timeout(engine, 1);
+
+	igt_spin_busywait_until_started(spin[1]);
+	igt_spin_free(i915, spin[1]);
+
+	igt_assert_eq(sync_fence_wait(spin[0]->out_fence, 1), 0);
+	igt_assert_eq(sync_fence_status(spin[0]->out_fence), -EIO);
+
+	igt_spin_free(i915, spin[0]);
+
+	gem_context_destroy(i915, ctx[1]);
+	gem_context_destroy(i915, ctx[0]);
+
+	igt_assert(enable_hangcheck(i915, true));
+	gem_quiescent_gpu(i915);
+
+	set_preempt_timeout(engine, saved);
+}
+
+#if 0
+static void each_engines(int fd)
+{
+	struct dirent *de;
+	DIR *dir;
+
+	dir = fdopendir(fd);
+	while (dir && (de = readdir(dir))) {
+		int engine = openat(engines, de->d_name, O_RDONLY);
+		char *name;
+
+		name = igt_sysfs_get(engine, "name");
+		if (!name)
+			continue;
+
+		igt_subtest_group {
+			igt_fixture {
+				igt_require(fstatat(engine,
+							"preempt_timeout_ms",
+							&st, 0) == 0);
+			}
+		}
+	}
+	closedir(dir);
+}
+#endif
+
+igt_main
+{
+	const struct intel_execution_engine2 *it;
+	int i915 = -1, engines = -1;
+
+	igt_fixture {
+		int sys;
+
+		i915 = drm_open_driver(DRIVER_INTEL);
+		igt_require_gem(i915);
+		igt_allow_hang(i915, 0, 0);
+
+		sys = igt_sysfs_open(i915);
+		igt_require(sys != -1);
+
+		engines = openat(sys, "engine", O_RDONLY);
+		igt_require(engines != -1);
+
+		close(sys);
+	}
+
+	__for_each_static_engine(it) {
+		igt_subtest_group {
+			int engine = -1;
+			char *name = NULL;
+
+			igt_fixture {
+				struct stat st;
+
+				engine = openat(engines, it->name, O_RDONLY);
+				igt_require(fstatat(engine,
+						    "preempt_timeout_ms",
+						    &st, 0) == 0);
+
+				name = igt_sysfs_get(engine, "name");
+				igt_require(name);
+			}
+			if (!name)
+				name = strdup(it->name);
+
+			igt_subtest_f("%s-idempotent", name)
+				test_idempotent(i915, engine);
+			igt_subtest_f("%s-invalid", name)
+				test_invalid(i915, engine);
+			igt_subtest_f("%s-timeout", name)
+				test_timeout(i915, engine);
+			igt_subtest_f("%s-off", name)
+				test_off(i915, engine);
+
+			free(name);
+			close(engine);
+		}
+	}
+
+	igt_fixture {
+		close(engines);
+		close(i915);
+	}
+}
diff --git a/tests/meson.build b/tests/meson.build
index 98f2db555..338da2e95 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -239,6 +239,7 @@  i915_progs = [
 	'i915_query',
 	'i915_selftest',
 	'i915_suspend',
+	'sysfs_preempt_timeout',
 ]
 
 test_deps = [ igt_deps ]